Air-drag apparatus for missiles



Jan l1, 1966 G. cHAKolAN ll-:TAL 3,228,634

AIR-DRAG APPARATUS FOR MISSILES 6 Sheets-Sheet l Filed July 18, 1963 Mimi55 lil! MMM

Jan. 1l, 1966 Filed July 18, 1965 G. CHAKOIAN ETAL AIR-DRAG APPARATUS FOR MISSILES 6 Sheets-Sheet 2 BY W Jan. 11, 1966 G. cHAKolAN ETAL 3,228,634

AIR-DRAG APPAMTUS FOR MIssILEs Filed July 18, 1963 6 Sheets-Sheet. 3

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Jan. 11, 1966 Filed July 18, 1963 G. CHAKOIAN ETAL AIR-DRAG APPARATUS FOR MIssILEs 6 Sheets-Sheet 4.

Jall- 11, 1966 G. CHAKOIAN ETAL 3,228,634

AIR-DRAG APPARATUS FOR MISSILES Jan. l1, 1966 G. CHAKOIAN ETAL AIR-DRAG APPARATUS FOR MISSILES Filed July 18, 1963 6 Sheets-Sheet 6 United States Patent O 3,228,634 AIR-DRAG APPARATUS FR MISSILES George Chakoian, Lincoln, and Russell T. Crowell, East Greenwich, RJ., and Alfred Ouellette, Brockton, Mass.,

assignors to the United States of America as represented by the Secretary of the Navy Filed July 18, 1963, Ser. No. 296,143 12 Claims. (Cl. 244-113) This invention relates to an apparatus for use in an airto-sea missile delivery system. More particularly, this invention relates to an apparatus for use in the control of the trajectory of an airborne missile.

In the past, airborne torpedoes were conventionally delivered to their respective water-borne targets by aircraft which today may be considered to be of the low speed variety. With the advent of high speed jet aircraft, however, a need has come into existence for a delivery system possessing a greater degree of accuracy than heretofore required.

One of the major factors affecting the accuracy of delivery of air-to-sea missiles is trajectory control. In order to have a consistently reproducible trajectory, and greater accuracy, it is necessary to control the missile from time of launch to immediately prior to water entry. This would .include control of deceleration in conjunction with positive stabilization of the missile throughout all phases of its descending flight.

Due to the launching speeds involved and the relatively small target area, trajectory control is essential. The major causes of trajectory inaccuracies are variations in operating time between time of launch and the operation of the stabilization equipment during descent. The missile must be decelerated from a launch velocity of about 500 knots to a terminal velocity of about 80 knots along a controlled trajectory without a lapse of time between operations where free fall would be experienced. Also, torpedo oscillations must be compensated for during this deceleration in order to prevent damage to the torpedo.

The subject invention fullls the needs described by providing deceleration, stabilization, and control trajectory to torpedoes launched from aircraft at speeds of the order of 500 knots. It also provides accuracy of delivery to a specified target by providing a constant drag force on the missile throughout its initial delivery trajectory.

An object of this invention is to provide an apparatus for use in an air-to-sea delivery system.

Another object is to provide an apparatus for the control of the trajectory of an airborne missile.

A further object is to provide an apparatus for the retardation and stabilization of an airborne missile during 4its descending flight.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

FIG. l is a perspective view of the apparatus showing the details of construction;

FIG. 2 is a side View showing the apparatus operatively carried by an aircraft;

FIG. 3 is a side view of the apparatus in the initial stage of opening;

FIG. 4 is a perspective view of the apparatus in the intermediate stage of opening;

FIG. 5 is a side view, partly in section, taken on line 5 5 of FIG. 3 showing in detail the ow control unit of the apparatus;

FIGS. 6 to 9 are side views partly in section, of the flow control unit, showing the sequence of operation during the performance of the apparatus; and

FIG. 10 is a perspective view showing the separation of the apparatus from the missile prior to water entry;

FIG. 11 is a schematic view showing the apparatus of this invention.

Similar numerals refer to similar parts throughout the several views.

As shown in FIG. 1, the device is composed of a plurality of vanes 11 and 12, some of which 11 are partially free moving and some of which 12 have their movements totally controlled by a central hydraulic system 13. All of the vanes are pivotally mounted exteriorly upon the end portion of a hydraulic cylinder 14 and each of the vanes is interconnected to the adjacent vanes by a series of fabric strips 15. The cylinder 14 is provided with a piston 15 slidably mounted on a central shaft 16 which is axially secured to the interior of the closed end of the cylinder 14. The piston 15 is provided with a collar 16 operatively connected to every other vane 12 by means of a link-rod assembly 17 which controls all the pivotal movements of such vanes 12. The cylinder 14 which contains a disposable oil 18, is also provided with a flexible hose 19 atlixed to the cylinder and communicating between the oil reservoir and the flow regulating unit 21 to be hereinafter described.

Referring to FIG. 2, the device is secured to the rear portion of the torpedo 22 by an air frame 23 which ts around the body of the missile. Prior to use, all the vanes are in the retracted position, the controlled vanes 12 forming an inner core around the hydraulic system 13 and the partially free moving vanes 11, which are closely aligned when retracted, forming an outer shell 24 for the unit. A locking band 25, which holds the partially free moving vanes 11 in position, is provided with an electrically actuated pyrotechnic reefing line-cutter 26 having the ability to instantaneously sever a 3000 pound nylon line with no escaping flame or heat to cause damage to surrounding materials. Once severed, a band retraction mechanism 27 composed of four spring and cable assemblies, will pull the band in the forward direction and hold it in position against the high velocity air stream. This action removes the clamping band from the outer vanes and prevents the possibility of the loose band striking the aircraft.

With the bands removed, springs 28 located in the rest pads 29 under the end portion of the vanes forming the outer shell will cause such vanes 11 to pivot open a suicient amount to permit the high velocity air stream to enter, forcing such vanes to suddenly open to an angle of about 31 as shown in FIG. 3. This condition is estimated to produce a drag having a load value of approximately 2250 pounds at a launch velocity of 500 knots at 50() feet. The outer vanes 11, which were free moving up this point, are now restrained Vfrom further movement by the fabric snubbing Astrips 15 which join such vanes to the inner control vanes 12. The load of opening shock is transmitted from the outer moving vanes 11 through the fabric strips 15 to the inner control vanes 12 whose movements are controlled by a hydraulic system hereinafter described. The vanes 11, 12 and the fabric strips 15 form the structure which provides the drag producing surfaces. Any .additional increase in drag area of the device is of a controlled nature from this point on. The device, which is functioning as an air-brake, will continue to open at a rate which will provide a constant drag of about 3000 pounds.

As shown in FIG. 4, the control vanes 12 are operatively connected to a hydraulic system 13 which serves to resist the opening movements of the vanes 12 against the force provided by dynamic air pressure. As heretofore described, 'the hydraulic system 13 is composed of a cylinder 14 provided with a piston 15 having a collar 16' operatively connected to each of the control vanes 12 by a separate link-rod assembly 17. The cylinder 13 contains oil 18 and is Iprovided with a hose 19 connecting the reservoir of oil 18 within the cylinder 14 to a fiow control unit 21. As the control vanes 12 begin to open from the poistion shown in FIG. 3 to that shown in FIG. 4, the piston 15, which -is guided on the center shaft 16 is caused to move into the cylinder 14. As a result, the pressure on the oil 18 increases forcing the oil out of the cylinder 13 into the hose 19 which directs it to a flow control unit 21 for programmed metering. It is this programmed metering of oil which maintains a constant drag during the opening of the device. When the device is fully open, as shown in FIG. 1, the drag will begin to diminish be- Y low theY 360:0 Ypound level.V

Programmed metering of the oil from the cylinder 14 through the hose 19 is accomplished iby a flow control unit 21 which is shown in FIG. 5. This unit, by controlling the rate of flow of oil 18 from the cylinder 14, regulates the outward movement of the control vanes 12 and the effective area of the lair brake, thereby maintaining a constant drag on the descent of the missile. However, this unit, in turn, is regulated by the pressure developed by a closed circiut hydraulic system 31, in response to movements of the central shaft 16.

The closed circiut hydraulic system 31 is composed of a reservoir 32 provided with a pressure shoe 33 responsive to movements of the central shaft 16. The reservoir 32 -is circumferentially disposed around the lower portion of the shaft 16 which passes through the mounting 34 secured to the airframe 23. As shown, the reservoir is defined by the shaft 16, the interior surface of the mounting 35, the flow control unit 36, and the pressure shoe 33. The latter shoe 33 because it -is secured to the central shaft 16 regulates the operational area of the reservoir 32 in response to movements of the shaft 16.

The ow control unit 21 is provided with a housing 38 having a high pressure chamber 39 within which is mounted a spring loaded hollow piston 41 of closed end construction. The head 42 of the hollow piston communicates with the reservoir 32, heretofore described, and the movement of the piston 41 in the chamber 39 is responsive to changes in pressure in the reservoir 32 caused by the constrictive movement of the pressure shoe 33 on the central shaft 16. The lower portion of the hollow piston 41 is in contact with a plate 42 backed by a plurality of balancing springs 43 which, to some extent, function to maintain a constant inward pressure on the piston 41 enabling it to remain at all times in contact with the fluid in the reservoir 32.

'Ille housing 38 of the unit is provided with an inlet chamber 44 and an exhaust chamber 45, both of which communicate with the pressure chamber 39 wherein the hollow piston 41 is mounted. The inlet chamber 44 is provided with an inlet fitting 46, which communicates with the exhaust hose 19, while the exhaust chamber 45 is provided with an exhaust fitting 47 which communicates with the atmosphere. The body of the hollow piston 41 is provided with a plurality of holes in spaced relationship around the periphery thereof, which in combination with the inlet chamber 44 `and the exhaust chamber 45 form two variable orifices.

When one course 48 of holes on the upper portion line wtih the edges of the chamber separat-ion sleeve v 51 and in this position, the metering orifice is fully open, as shown. This alignment depends on the position of the piston 41 in the chamber 39, which is directly influenced by the pressure exerted by the reservoir 32 and is hereinafter described in detail. It is the force relationship between the balancing spring 43 and the fluid pressure in the reservoir 32 that positions the piston 41 to the required orifice area.

Upon initial shock, when the vanes 11 open to their initial position, as shown in FIG. 2, the vane 11 develops a drag and the load of such drag pulls the shaft 16 outwardly through the mounting 34. As a result, the pressure shoe 33 attached to the central shaft 16 constricts the area of the reservoir 32 developing a pressure which, in turn, is transmitted to the head 42 of the piston 41. This is because the piston 41 forms a part of the closed Ycircuit hydraulic system 31 as shown in FIG. Y5. Thislaction forcesV the body of the piston 41 outwardly against the spring actuated plate 42, and the upper course 48 of holes adjacent the inlet chamber 44 are moved into alignment with the separation sleeve 51 between the inlet chamber 44 and the exhaust chamber 45. In this position, the inlet port is fully closed, as shown in FIG. 6.

At this point, the ow of oil from the main cylinder into the hose 19 is restricted and a back-pressure builds up in the main cylinder 14 preventing further movement of the piston 15 and the related movement of the vanes 12. When the vanes 12 are locked in position, as described, the area of drag defined by the vanes 11, 12 and the snubbing strips 15 assumes a set value. As a result, the descending torpedo is decelerated but the drag developed by the defined area of the device decreases and a lesser load is transmitted through the central shaft 16 to the pressure shoe 33. As the latter shoe releases its pressure on the confined reservoir 32, the springs 43, in sequence, overcome the pressure transmitted to the piston head 42 by the reservoir 32. The piston will then oscillate in an inwardly direction against the reservoir 32 through the position shown in FIG. 7 to the position shown in FIG. 8.

As shown in FIG. 8, the inlet port is open and the oil 18 exhausting from the main cylinder 14 enters the valve metering chamber through the inlet fitting 19. When the oil is restricted in the chamber, the pressure therein will equal the pressure in the main cylinder minus negligible pressure losses due to the length of connecting line from the cylinder to the flow control unit. The oil will then meter through the variable orifice into the by-pass port of the piston body and through the plurality of exhaust holes 49 into the exhaust chamber 45 and out to the atmosphere through the exhaust fitting 47. There is a substantial difference between the area of the metering orifice 48 and the exhaust fitting 47, and as a result the oil will be exhausted to the atmosphere at a considerably lower pressure than the pressure in the system. The maximum exhaust pressure has been estimated to be about 37 p.s.i.

When the main cylinder 14 is relieved of some amount of oil 18, the main piston 15 therein will move further into the cylinder 14 and the vanes 12, in turn, will be allowed to pivot further in an outwardly direction. This develops a greater drag due to the increased area and an increased load is transmitted to the central shaft 16 promoting the sequence of operations heretofore encountered upon initial shock. These operations will continue until the ow control unit 21 assumes the position shown in FIG. 9 when the oil is fully exhausted from the main cylinder and the device progresses to the fully open position as shown in FIG. 1. Prior to this, whenever the drag-load decreases, the valve through the described sequence of operations will open and whenever the dragload increases, the valve again will be closed as heretofore explained.

As described, the drag load is sensed by the linear movement of the center shaft along the longitudinal axis of the air-brake. The drag loads acting on the air-brake vanes are transmitted to the close circuit hydraulic system of the iiow control unit by two paths. One path is from the vanes through the link-rods to the main piston which fits in the cylinder attached to the center shaft. The other path is directly from the vanes through the pivot pins to the center shaft. The amount of force transmitted through each path varies as the air-brake opens to its full diameter. This is because of the continually increasing angle of the link-rods which connect the main vanes with the piston. However, the closed circuit hydraulic system of the ilow control unit always receives the total drag load because the loads from the two sources are transmitted through one common shaft. The drag force is thus sensed by generating a lluid pressure in the reservoir and this pressure serves to set the metering area of the llow control unit.

At a predetermined altitude, the air frame and the airbraking device will be jettisoned. This may be accomplished by means of a timing device which will initiate the release mechanism prior to water impact so that all suspension and stabilization equipment will be cleared of the torpedo. Air delivery of the torpedo will have been completed as shown in FIG. 1G, and the torpedo will be ready for its water trajectory without any risk of propeller damage or bent shaft.

Obviously, many modifications and variations of the present invention are possible in 'the light of the above teaching. For instance, when the air-brake is inoperative, prior to use, the oil from the main cylinder may be prevented from leaking by means of a plug which may be fitted over the exhaust fitting. Immediately upon the initial opening of the device, the oil pressure in the system builds up and the plug will be jettisoned. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specillcally described.

We claim:

1. An apparatus for use in the retardation and stabilization of airborne missiles during descending flight comprising hydraulic means having a base member,

a plurality of vane members pivotally mounted in spaced relationship around said base member,

each of said vane members -being interconnected to adjacent vane members yby a plurality of webbing members, every other of said vane members having a body portion coupled through mechanical linkage to said hydraulic means whereby a compressive pressure is transmitted from said vane members through said mechanical linkage to said hydraulic means when dynamic air pressure acts on said vane members,

said compressive pressure forcing tluid from said hydraulic means, and valving means cooperating with said hydraulic means for the programmed metering of said lluid from said hydraulic means, thereby controlling the pivotal movement of said vane members on said base.

2. An apparatus for use in the retardation and stabilization of airborne missiles during descending flight comprising hydraulic means having a base member,

a plurality of vane members pivotally mounted in spaced relationship around said base member,

each of said vane members interconnected to adjacent vaue members -by a plurality of webbing members, every other of said vane members having a body portion coupled through mechanical linkage to said hydraulic means whereby a compressive pressure is transmitted from said vane members through said mechanical linkage to said hydraulic means when dynamic air pressure acts on said vane members,

said compressive pressure forcing fluid from said hydraulic means, and valving means connected to said hydraulic means for the programmed metering of said fluid from said hydraulic means in response to movements of said base by variations of total load of drag transmitted from said vane members and said webbing members to said base thereby controlling the pivotal movement of said vane members on said base.

3. An apparatus for use in the retardation and stabilization of airborne. missiles during descending ilight comprising hydraulic means having a base member,

a plurality of vane members pivotally mounted in spaced relationship around said base member,

a plurality of webbing members interconnecting each of said vanes to adjacent vane members,

a mechanical linkage connecting the body portion of every other of said vanes to said hydraulic means whereby compressive pressure is transmitted from said vane members through said linkage to said hydraulic means when dynamic air pressure acts on said vane members,

said compressive pressure forcing fluid from said hydraulic means, and

valving means connected to said hydraulic means for the programmed metering of said fluid from said hydraulic means thereby controlling the pivotal movement of said vane members on said base.

4. An apparatus for use in the retardation and stabilization of airborne missiles during descending ilight comprising hydraulic means having a base member,

a plurality of vane members pivotally mounted in spaced relationship around said base member,

a plurality of webbing members interconnecting each of said vanes to adjacent vane members,

a mechanical linkage connecting the body portion of every other of said vanes to said hydraulic means whereby compressive pressure is transmitted from said vane members through said linkage to said hydraulic means when dynamic air pressure acts on said vane members,

said compressive pressure forcing duid from said hydraulic means, and

valving means connected to said hydraulic means for the programmed metering of said fluid. from said hydraulic means in response to movements of said base by variations of tota-l load of drag transmitted from said vane members and said webbing members to said -base thereby controlling the pivotal movement of said vane members on said base.

5. An apparatus for use in the retardation and stabilization of airborne missiles during descending ilight comprising a hydraulic cylinder within which is housed a iluid,

said cylinder tted with a movable piston having a dependent rod provided with a collar,

a shaft passing axially through said collar, rod, and piston and having one end axially secured within said cylinder,

a ilow line integral said cylinder and communicating with said iluid,

a pressure-regulated valve fitted on said line and controlling the ilow of said iluid in said line,

said valve communicating with a reservoir within which is housed a pressure means,

said pressure means integral the free end of said shaft and responsive in changes of pressure to movements of said shaft, and

a plurality of vanes pivotally mounted on the exterior of said cylinder,

each of said vanes being interconnected to another by means of webbing and every other of said vanes having a mid-portion connected to said collar by means of a tie-bar.

6. An apparatus for use in the retardation and stabilization of airborne missiles during descending flight comeach of said vanes interconnected to the adjacent vanes prising: by a plurality of webbing members,

a hydraulic cylinder fitted with a movable piston having every other of said vane members mechanically linked a dependent rod around which is a collar, to said collar.

said cylinder containing a disposable fluid, 9. An apparatus for use in the retardation and stabilizaa plurality of vanes pivotally mounted in spaced relation of airborne missiles comprising:

tion exteriorly on the end portion of said cylinder, a cylinder one end of which is of closed construction each of said vanes being interconnected to adjacent and the other end of which is open,

vanes by webbing, said cylinder containing a disposable fluid, a plurality of tie-rods connecting the mid-portion of 10 an elongated central shaft one end of which is secured said vanes to said collar, to said closed end of said cylinder and the other end a longitudinally movable shaft passing axially through of which extends axially out of said cylinder,

said collar, said rod, and said piston and axially a piston having a dependent rod provided with a collar, secured within said cylinder, said piston, rod, and collar slidably mounted on sai-d shaft provided withapressure shoe, said shaft and said piston operatively fitted in a pressure actuated valve provided with a pressure said cylinder,

transmitting reservoir communicating with said valve, a flow-line communicating with said disposable fiuid said reservoir containing a second fluid and housthrough the side of said cylinder,

ing said pressure shoe, a spring-actuated valve provided on said flow-line for a flow-line communicating between said disposable control of the iiow of said uid in said line,

fluid in said cylinder and said valve. a pressure shoe provided on said shaft, 7. An apparatus for use in the retardation and stabilizaa reservoir containing a control fluid communicating tion of airborne missiles during descending flight comwith said adjustable valve, prising: said reservoir housing said pressure shoe for the said reservoir containing a second fiuid and housing said pressure shoe whereby pressure is transmitted from said shaft by means of said shoe through said reservoir to open and close a hydraulic cylinder fitted with a movable piston having compression of sai-d control fiuid,

a dependent rod around which is a collar, said control iiuid transmitting pressure to said adsaid cylinder containingadisposable fluid, justable valve thereby controlling the flow of a plurality of vanes pivotally mounted exteriorly on said disposable fiuid from said cylinder,

said cylinder, a plurality of free moving vanes one end of each of each of said vanes being interconnected to adjacent which is pivotally mounted exteriorly on said closed vanes by webbing, end of said cylinder, a plurality of tie-rods connecting every other of said a plurality of control vanes one end of each of which vanes to said collar, is pivotally mounted exteriorly on said closed end a longitudinally movable shaft passing through said of said cylinder and collar, said rod, and said piston and secured within a plurality of tie-rods operatively connecting the midsaid cylinder, portion of said control vanes to said collar, and

said shaft provided withapressure shoe, a plurality of webbing members interconnecting said a pressure actuated valve provided with a pressure free moving vanes with said control vanes.

transmitting reservoir communicating with said 10. An apparatus for use in the retardation and stabilivalve, zation of airborne missiles comprising:

a cylinder having one end of open construction and the other of closed construction,

said cylinder containing a disposable oil, an elongated shaft having one end axially secured to the said valve, and closed end of said cylinder, a flow-line communicating between said disposable a piston being operatively fitted in the open end of said fluid in said cylinder and said valve whereby said cylinder and slidably mounted on said shaft, fluid fiows through said ow line to said valve resaid piston having a dependent rod provided with sponsive to movements of said piston by said vanes a collar, through said tie-rods. a flow-line integral said cylinder and communicating 8. An apparatus for use in the retardation and stabilizawith said oil, tion of airborne missile comprising: a spring-actuated valve on said flow-line for control of a cylinder one end of which is open, said oil,

said cylinder containing a disposable oil, a reservoir having a passage communicating with said an elongated central shaft one end of which is axially valve,

secured within said cylinder and the other end of said reservoir containing a second fluid, which axially extends out of said cylinder, a pressure shoe provided on the free end of said shaft a piston having a dependent rod provided with a collar, and housed in said reservoir,

said piston, rod, and collar slidably mounted on said shoe transmitting pressure to said valve said shaft and said piston operatively fitted in through said second fluid thereby controlling said cylinder, fiow in said line, a flow-line communicating with said disposable oil a plurality of control vanes having one end pivotally through the side of said cylinder, mounted on the outer surface of said cylinder, a spring-actuated valve provided on said flow-line for a plurality of tie-rods operatively connecting the midcontrol of the flow of said oil in said line, portion of said control vanes to said collar, a pressure shoe provided on said shaft, a plurality of free moving vanes having one end pivota reservoir containing a control uid communicating ally mounted on the outer surface of said cylinder,

with said adjustable valve, and

said reservoir housing said pressure shoe for the a plurality of webbing members operatively connectcompression of said control fluid, ing said free moving vanes to said adjacent control said control fluid transmitting pressure to said vanes whereby,

adjustable valve thereby controlling the flow of said piston, responsive to movement of said vanes, said disposable iiuid from said cylinder, and forces oil from said cylinder into said line and a plurality of vanes pivotally mounted in spaced relasaid valve controls the dispensing of oil from tionship exteriorly around said cylinder, said line responsive to movements of said shaft.

11. A Valve for use in an air-to-sea missile delivery sysstem comprising:

a body member having an elongated chamber of open end construction provided with an inlet fitting and an exhaust fitting,

a longitudinally movable hollow cylinder of closed end construction housed in said chambers,

said cylinder provided with a peripheral array of orifices around the upper and lower portion thereof,

said upper array of orifices aligned with said inlet fitting and said lower array of orifices aligned with said exhaust fitting whereby fiuid may flow from said inlet fitting through said upper orifice array into said cylinder and out said lower orifice array into said exhaust fitting,

a closed circuit hydraulic system communicating with the upper end of said cylinder,

said system transmitting a varying downward pressure to said cylinder, and

a spring-actuated plate in contact with the lower end of said cylinder,

said plate transmitting an upper pressure to said cylinder whereby in response to an overbearing downward pressure, said cylinder moves along the longitudinal axis of said chamber to disalign said arrays of orifices with respect to said fittings.

12. A Valve for use in in air-to-sea missile delivery system comprising:

a body member having an elongated chamber of open end construction provided with an inlet fitting and an exhaust fitting,

a hollow cylinder of closed end construction housed in said chamber and movable along the longitudinal axis thereof,

said cylinder provided with a peripheral array of orifices around the upper and lower portion thereof,

said upper array of orifices aligned with said inlet fitting and said lower array of orifices aligned with said exhaust fitting whereby fluid may flow from said inlet fitting through said upper orifice array into said cylinder and out said lower orifice array into said exhaust fitting, a reservoir communicating with the upper end of said cylinder, a pressure actuating shoe housed in said reservoir,

said reservoir transmitting a varying downward pressure to said cylinder in response to pressure actuated by said shoe, a spring actuated plate in contact with the lower end of said cylinder,

said plate transmitting an upward pressure to said cylinder, whereby in response to an overbearing downward pressure, said cylinder moves along the longitudinal axis of said chamber to disalign said arrays of orifices with respect to said fittings.

References Cited by the Examiner UNITED STATES PATENTS 1,537,713 5/1925 Sperry et al 1024 2,969,211 1/ 1961 Von Saurma 244-142 3,047,259 7/ 1962 Tantnall et al 244-138 3,114,315 12/1963 Trump 102-4 MILTON BUCHLER, Primary Examiner.

SAMUEL FEINBERG, Examiner.

STAHL, L. C. HALL, Assistant Examiners, 

1. AN APPARATUS FOR USE IN THE RETARDATION AND STABILIZATON OF AIRBORNE MISSILES DURING DESCENDING FLIGHT COMPRISING HYDRAULIC MEANS HAVING A BASE MEMBER, A PLURALITY OF VANE MEMBERS PIVOTALLY MOUNTED IN SPACED RELATIONSHIP AROUND SAID BASE MEMBER, EACH OF SAID VANE MEMBERS BEING INTERCONNECTED TO ADJACENT VANE MEMBERS BY A PLURALITY OF WEBBING MEMBERS, EVERY OTHER OF SAID VANE MEMBERS HAVING A BODY PORTION COUPLED THROUGH MECHANICAL LINKAGE TO SAID HYDRAULIC MEANS WHEREBY A COMPRESSIVE PRESSURE IS TRANSMITTED FROM SAID VANE MEMBERS THROUGH SAID MECHANICAL LINKAGE TO SAID HYDRAULIC MEANS WHEN DYNAMIC AIR PRESSURE ACTS ON SAID VANE MEMBERS, SAID COMPRESSIVE PRESSURE FORCING FLUID FROM SAID HYDRAULIC MEANS, AND VALVING MEANS COOPERATING WITH SAID HYDRAULIC MEANS FOR THE PROGRAMMED METERING OF SAID FLUID FROM SAID HYDRAULIC MEANS, THEREBY CONTROLLING THE PIVOTAL MOVEMENT OF SAID VANE MEMBERS ON SAID BASE. 